using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.IO;
namespace Evaluation.WYP_DSEARCH
{
/// <summary>
/// Summary description for WebForm2.
/// </summary>
public class WebForm2 : Class.PageBase
{
protected System.Web.UI.WebControls.Button cmdUpload;
protected System.Web.UI.WebControls.Label lblMessage;
protected System.Web.UI.HtmlControls.HtmlInputFile File1;
private void Page_Load(object sender, System.EventArgs e)
{
// Put user code to initialize the page here
}
#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeComponent();
base.OnInit(e);
}
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.Load += new System.EventHandler(this.Page_Load);
this.cmdUpload.Click += new System.EventHandler(this.cmdUpload_Click);
}
#endregion
private void DeleteFile(string strFileName)
{//Delete the from the server
if(strFileName.Trim().Length>0)
{
FileInfo fi=new FileInfo(strFileName);
if(fi.Exists)
{
fi.Delete();
}
}
}
private void cmdUpload_Click(object sender, System.EventArgs e)
{
if((File1.PostedFile!=null)&&(File1.PostedFile.ContentLength>0))
{//determine file name
string sFileName=System.IO.Path.GetFileName(File1.PostedFile.FileName);
try
{
if(File1.PostedFile.ContentLength<=lMaxFileSize)
{
//Save file on disk
File1.PostedFile.SaveAs(sFileDir+sFileName);
lblMessage.Visible=true;
lblMessage.Text="File "+sFileDir+sFileName+" Uploaded Successfull";
}
else
{
lblMessage.Visible=true;
lblMessage.Text="File size if over the limit of "+lMaxFileSize;
}
}
catch(Exception)
{
lblMessage.Visible=true;
lblMessage.Text="An error occured.Please try again!";
DeleteFile(sFileDir+sFileName);
}
}
}
运行出现:
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
Source Error:
Line 52: private void Button1_Click(object sender, System.EventArgs e)
Line 53: {
Line 54: if(file1.PostedFile.FileName!="")
Line 55: {
Line 56: string sFile=file1.PostedFile.FileName;